1. Field of the Invention
The present invention relates to an Organic Light Emitting Display (OLED) and its method of fabrication, and more particularly, to an OLED and its method of fabrication in which a photochromatic layer is formed on a first surface of a transparent substrate of an OLED so that it is possible to realize a light emitting display of high visibility and contrast even when intense external light is incident.
2. Description of the Related Art
An OLED is formed of uniform and flat thin films. Also, in the OLED, an electrode that emits light is formed of a transparent conductive thin film and the opposite electrode is formed of aluminum or another heat resistant metal. Since the metal thin films have a high reflectivity, when intense light (light emitted from a strong light source, such as solar rays) is directly incident from an external light source, the clarity of a screen deteriorates.
Therefore, in order to prevent the displayed image from deteriorating due to the reflection of external light, a reflection preventing film is formed on the surface of or inside the display. According to such a technology, for example, in OLEDs of common and charged structures, a diamond like carbon thin film of low reflectivity is formed between a metal electrode film and an insulating film, between an insulating film and a fluorescent film, or between a metal conductive film and a fluorescent film so that it is possible to minimize reflection of the external light from the metal electrodes and to thus increase the efficiency of electrons irradiated into the fluorescent film.
As described above, when a reflection preventing layer is inserted in order to prevent the external light from being reflected from the metal thin films, it is possible to see a clear image under an intense external light source. However, when the external light source does not exist, the reflection preventing layer is not required. However, the reflection preventing layer is still present so that the emission efficiency of the OLED is reduced.